1. Field of the Invention
This invention relates to paving stones. More particularly, this invention relates to a paving stone having the appearance of four connected octagonal shaped paving stones having a square hole at the center capable of being laid with other like paving stones to form a stable load carrying surface.
2. Description of the Prior Art
Paving stones of differing shapes have been employed in the construction of traffic-carrying surfaces such as roadways, footways, embankments and pool decks. Typically, the paving stones are made of concrete which is formed in a desired shape in a mold, and then cured under high pressure where the concrete is compacted and hardened. The hardened paving stone is then removed from the mold and exposed to ambient air to cure. The method by which such paving stones can be made is well known in the art and forms no part of my invention. Hence, methods for making paving stones will not be addressed further except to note that the shape of the various molds used to form prior art paving stones must be modified so as to conform to the shape of my paving stone.
In laying the paving stones, the under-surface is first prepared in a known fashion to provide a smooth, flat surface. The paving stones are then placed on the under-surface such that their vertical or peripheral walls or lateral edges come into close contact. The gaps between the lateral edges may be filled either with mortar, concrete, or other such solidifying spacer elements, or, preferably, with sand which is simply poured into the gaps in a known manner. The traffic load encountered by surfaces constructed in the above manner can vary from as light as pedestrian traffic to as heavy as several ton trucks and forklifts.
Known paving stones come in a wide variety of shapes from square and rectangular to multi-sided and irregular. Among the known paving stones when viewed from the top include paving stones which have a simple geometric shape such as a rectangle, a square, a hexagon, or an octagon. These paving stones are less desirable than other types of stones hereinafter discussed because their shapes preclude an interlock joint between adjacent paving stones. Additionally, proper utilization can require greater material and care than other paving stones and are often not satisfactory in use. For example, if such paving stones were placed in the manner expected of my invention, i.e., with sand between them, the surface would not be stable because there is no interlock. Furthermore, because there is no interlock, long, straight channels are more easily formed between the elements, thus, permitting rain, for example, to wash away the sand further reducing the load carrying stability of the ground cover formed with those elements. Hence, such paving stones would typically require mortar or concrete between elements. Mortar or concrete is typically more expensive than sand and is more difficult to work with. One example of a known and simple geometric shape paving stone is French Patent No. 1.073.200.
Another type of paving stone is one wherein, from a top plan view, the paving stone looks substantially rectangular but the edges are deformed in such a manner as to interlock when laid next to an adjacent, identical stone. An example of this type of paving stone is shown in U.S. Pat. No. 1,379,440. Also included in this type of paving stone are multi-faced irregularly shaped paving stones. The paving stones of this type overcome some of the drawbacks of paving stones discussed in the preceding paragraph because they may be interlocked. However, they are less attractive from an aesthetic standpoint. Moreover, these paving stones generally may not be intermixed with other differently shaped paving stones, as would be possible with paving stones described in the preceding paragraph to permit a wide variety of patterns to be created.
Yet another type of paving stone includes two or more sections having a simple geometric shape which are combined into one integral paving stone. Examples of such paving stones are disclosed in U.S. Pat. Nos. 4,544,305; 4,128,357; and German Gebrauchsmuster No. 7,409,912. The primary advantage of such an integral paving stone is that it can interlock for durability and stability.
Accordingly, it is an object of the present invention to provide a paving stone that is simple and economical to manufacture. Another object of the present invention is to provide a paving stone that is easy to lay in a running bond pattern, a modified running bond pattern, a stack bond pattern or a basket weave pattern. Yet another object of the present invention is to provide a paving stone that may incorporate a separate colored paving stone to provide a wide variety of mosaic designs. Another object of the present invention is to provide a paving stone having a central hole to impart an appearance to the single paving stone of four separate octagonal shaped paving stones. Yet another object of the present invention is to provide a paving stone with a central hole to facilitate hand gripping and the use of a mechanized handling system and/or a mechanized laying system. Another object of the present invention is to provide a paving stone that may be laid upon a suitable foundation and interlocked with adjacent paving stones in a running bond pattern to form a unitary surface.